Spring mounting structure in seat back

Abstract

[Purpose] To provide a sinuous spring mounting structure in a seat back, which can realize a lightweight and simplified structure of a seat back frame of the seat back. A sinuous spring or S-spring 10 used in the present invention has left and right end portions 10 a and 10 b which include two curved regions 10 a U and 10 b U, respectively. A seat back frame 7 includes left and right cylindrical side frame portions 9 L and 9 R. One spring mounting portion 11 for allowing the left end portion 10 a of the S-spring 10 to be mounted thereto is formed in an outwardly-facing lateral surface area of the left cylindrical side frame portion 9 L, whereas the other spring mounting portion 11 for allowing the right end portion 10 b of the S-spring 10 to be mounted thereto is formed in an outwardly-facing lateral surface area of the right cylindrical side frame portion 9 R. Those two spring mounting portions 11 may be embodied by first and second hole portions 11 A- 1 and 11 A- 2 , respectively, for example, in which case, two distal ends 10 a E and 10 b E of the S-spring 10 may be inserted and hookingly secured in the first and second hole portions 11 A- 1 and 11 A- 2 , respectively, such that the two curved regions 10 a U and 10 b U of the S-spring 10 are closely contacted on and along two outer circumferential surfaces of the left and right cylindrical side frame portions 9 L and 9 R, respectively.

1 . A sinuous spring mounting structure in a seat back including a seat back frame forming a part of the seat back, said seat back frame including a first cylindrical portion and a second cylindrical portion, wherein said first and second cylindrical portions are disposed in an opposedly-facing relation with each other, and wherein said sinuous spring mounting structure is adapted for allowing at least one sinuous spring to be mounted to said first and second cylindrical portions so as to be extended therebetween,
 said sinuous spring mounting structure being characterized in that:
 said at least one sinuous spring has: a first end portion including a curved region; and 
   a second end portion including a curved region;
 said first cylindrical portion of said seat back frame includes a first mounting portion for allowing said first end portion of said at least one sinuous spring to be mounted thereto; and 
 said second cylindrical portion of said seat back frame includes a second mounting portion for allowing said second end portion of said at least one sinuous spring to be mounted thereto; 
   and characterized in that said first and second end portions of said at least one sinuous spring are mounted to said first and second mounting portions, respectively, in such a manner that said curved region of said first end portion is contacted on and along an outer circumferential surface of said first cylindrical portion, whereas said curved region of said second end portion is contacted on and along an outer circumferential surface of said second cylindrical portion.   
     
     
         2 . The sinuous spring mounting structure in the seat back as described in  claim 1 , wherein said first and second end portions of said at least one sinuous spring are each coated with a resin material. 
     
     
         3 . The sinuous spring mounting structure in the seat back as described in  claim 1 , wherein said first mounting portion comprises a first hole portion configured to allow said first end portion of said at least one sinuous spring to be inserted and hookingly engaged therein, whereas said second mounting portion comprises a second hole portion configured to allow said second end portion of said at least one sinuous spring to be inserted and hookingly engaged therein, wherein said first end portion is inserted and hookingly secured in said first hole portion, with said curved region of said first end portion being contacted on and along said outer circumferential surface of said first cylindrical portion, and wherein said second end portion is inserted and hookingly secured in said second hole portion, with said curved region of the second end portion being contacted on and along said outer circumferential surface of said second cylindrical portion. 
     
     
         4 . The sinuous spring mounting structure in the seat back as described in  claim 3 , wherein said first and second end portions of said at least one sinuous spring are each coated with a resin material. 
     
     
         5 . The sinuous spring mounting structure in the seat back as described in  claim 1 , wherein said first mounting portion comprises a first truncated-conical hole portion formed in said first cylindrical portion, said first truncated-conical hole portion opening divergent in a direction from an inside to the outer circumferential surface of said first cylindrical portion, wherein said first truncated-conical hole portion therefore has a sloped surface that becomes progressively narrow in area in a direction from the outer circumferential surface to the inside of said first cylindrical portion, wherein, similarly to said first mounting portion, said second mounting portion comprises a second truncated-conical hole portion formed in said second cylindrical portion, said second truncated-conical hole portion opening divergent in a direction from an inside to the outer circumferential surface of said second cylindrical portion, wherein said second mounting portion therefore has a sloped surface that becomes progressively narrow in area in a direction from the outer circumferential surface to the inside of said second cylindrical portion, wherein said first end portion of said at least one sinuous spring is inserted and hookingly secured in said first truncated-conical hole portion, with said curved region of said first end portion being contacted on and along said outer circumferential surface of said first cylindrical portion, and wherein said second end portion of said at least one sinuous spring is inserted and hookingly secured in said second truncated-conical hole portion, with said curved region of said second end portion being contacted on and along said outer circumferential surface of said second cylindrical portion. 
     
     
         6 . The sinuous spring mounting structure in the seat back as described in  claim 5 , wherein said first and second end portions of said at least sinuous spring are each coated with a resin material. 
     
     
         7 . The sinuous spring mounting structure in the seat back as described in  claim 1 , wherein said first mounting portion comprises a first recessed mounting portion formed in said first cylindrical portion so as to extend in a circumferential direction along said outer circumferential surface of said first cylindrical portion, wherein said second mounting portion comprises a second recessed mounting portion formed in said second cylindrical portion so as to extend in a circumferential direction along said outer circumferential surface of said second cylindrical portion, wherein said first end portion as well as said curved region thereof, which are formed in said at least one sinuous spring, are both hookingly engaged in and along said first recessed mounting portion, and wherein said second end portion as well as said curved thereof, which are formed in said at least one sinuous spring, are both hookingly engaged in and along said second recessed mounting portion. 
     
     
         8 . The sinuous spring mounting structure in the seat back as described in  claim 5 , wherein said first and second end portions of said at least sinuous spring are each coated with a resin material.